resumo
This work addresses the evaluation of the ability of ionic liquid cations on the formation of aqueous biphasic systems (ABS's), with K(2)HPO(4) or a mixture of inorganic salts, K(2)HPO(4)/KH(2)PO(4), aiming at controlling the pH values of the coexisting aqueous phases. Using chloride-based ionic liquids, the effects of the cation core, the length of the alkyl side chain, and the positional isomerism on ABS formation ability were investigated. All binodal curves were determined by the cloud-point titration method at 298 K. From the obtained phase diagrams it is shown that the biphasic area increases with the cation side chain length, from ethyl to hexyl chains, although for longer chains, an inversion on the binodal curves sequence appears due to the self-aggregation of the longer chain ionic liquids in aqueous solutions. The influence of the cation core and the positional isomerism of the ionic liquids on their ability to form ABS closely correlates with the ionic fluid affinity for water.
palavras-chave
PHASE-DIAGRAM DATA; 2-PHASE SYSTEMS; SALTING-OUT; 298.15 K; 1-BUTYL-3-METHYLIMIDAZOLIUM TETRAFLUOROBORATE; MUTUAL SOLUBILITIES; PENICILLIN-G; AMINO-ACIDS; PLUS SODIUM; EXTRACTION
categoria
Thermodynamics; Chemistry; Engineering
autores
Ventura, SPM; Sousa, SG; Serafim, LS; Lima, AS; Freire, MG; Coutinho, JAP
nossos autores
Luísa Seuanes Serafim
Professor Auxiliar
Mara Guadalupe Freire Martins
Investigador Coordenador
Sónia Patrícia Marques Ventura
Professor AuxiliarGrupos
G4 - Materiais Renováveis e Economia Circular
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
This work was financed by national funding from FCT-Fundacao pars a Ciencia e a Tecnologia, through the project PTDC/QUI-QUI/121520/2010. The authors also acknowledge FCT for the grant BII of S.G.S. and doctoral and post-doctoral grants SFRH/BD/37830/2007 and SFRH/BPD/41781/2007 of S.P.M.V. and M.G.F., respectively.